Vibration Mount Load Distribution Determination

[natebott]

I am working on a large piece of equipment which is mounted using 10 pads. I have the weight, and mounting dimensions. I know that any calculation is a best estimate, not 100% accurate, but I want to be as close as I can be. What is the best method to use to calculate the approximate loading at each mounting pad?

 

[Twoballcane]

loading at static or dynamic? If static, it is a center of gravity study. If you know the dynamic, you can factor in the G loads.

Tobalcane
"If you avoid failure, you also avoid success."

 

[natebott]

I know the static loading only. I have through a 3d model the position of the center of mass as well.

 

[Twoballcane]

Great, now you can do a free body diagram where Sum of F = 0 and Sum of M = 0 and you then you can find the resultant loads both in the vertical and horizontal directions at each pad.

Tobalcane
"If you avoid failure, you also avoid success."

 

[BobM3]

With 10 mounting points it will be overconstrained. You'd either have to have some ability to adjust the position of some of the pads or have some compliance to equalize/adjust the load distribution.

 

[MikeHalloran]

With 10 pads, I'm guessing it's something like a big generator, where each 'pad' would be equipped with several stiff springs and a jacking screw. Somebody knows the spring rate, so you can estimate to what extent the unit will be off-level when it's first dropped. You can sort of estimate the load distribution, assuming the skid and the floor are both planar.

Then the installers will crank it level with the jackscrews, which will move the loads around a bit.



Mike Halloran
Pembroke Pines, FL, USA